In the field of medical imaging, prior to the digitization of medical imaging, medical-imaging users (e.g., radiologists) would analyze physical film printed images in light boxes, and use physical devices such as magnifying glasses, rulers, grease pencils, and their hands to manipulate the physical printed medical images in order to interpret and diagnose the images. With the digitization of medical imaging, the physical film became a digital image, displayable on a computer monitor. A medical-imaging system became a computer application or collection of computer applications, which require a computer or computers to operate. At present, users interact with medical-imaging systems through a mouse and keyboard. Commands to the medical-imaging system are typically invoked through mouse and/or keyboard interactions.
For instance, at present, radiologists typically want their Picture Archiving and Communication System (PACS) diagnostic workstation interaction to be as efficient as possible, with significant interest in shaving as little as a few seconds off the completion time of reading an image study for a patient. The radiologists also typically desire the interface to be comfortable for long periods of use to avoid fatigue that may lead to repetitive stress injuries (RSI). While the mouse has been a remarkably useful graphical user interface (GUI) interaction device, it is not without issues for highly repetitive image and graphics intensive use. Radiologists often perform the same image navigation and manipulation tasks such as scrolling a stack of images, zooming and panning images and adjusting image window and level hundreds of times a day. This may lead to mouse related fatigue, and in severe cases RSI. The PACS diagnostic workstation software typically relies on standard GUI conventions such as drop down menus, graphical tools, and keyboard and/or mouse shortcuts which may not be the most efficient approach for these common image operations.
In this regard, for image-intensive computing with rich graphical user interfaces, the mouse is showing its age. The mouse constrains the interaction to a single x, y point on the display with buttons to make selections and initiate modes of operation, such as click and drag. Most modern computer mice also have a special purpose scroll mechanism, often a wheel. Much of the human hand and finger capabilities and dexterity are not utilized with a mouse, and a mouse is limited to only one hand. Using the mouse for long periods of time tends to cause fatigue and repetitive stress symptoms due to the need to grasp the device and repeatedly perform small stressing motions of the fingers to click buttons.
For alphanumeric text entry, and initiating commands, keyboards have remained much the same for many decades and it has been difficult to find alternatives that perform better at text entry, for most users. When used as an input device for medical-imaging systems, some form of keyboard may remain in use for text entry for a long time to come. However, another common purpose for which keyboards are used with medical-imaging systems is for shortcuts to operations generally also available with the mouse but at the cost of navigation time and additional mouse clicking. The trade-off with mapping functions to keyboard shortcuts is the user has to learn and remember non-intuitive mappings of functions to keys, and most people have trouble remembering more than a few.
To address some of the drawbacks associated with using a mouse and keypad, tablet devices are currently being utilized for multitouch input to control image operations. For workstation computers primarily dedicated to a singular purpose, such as a diagnostic medical imaging workstation, a computer aided design workstation, a graphic art workstation, or a scientific computing workstation, the use of such a multitouch tablet can be enhanced with an overlay that physically divides the sensing surface of the tablet into various shaped regions. While the overlay is useful, the overlay may inadvertently move relative to the sensing surface of the underlying tablet, thereby causing the overlay to become misaligned. Some users may tape the overlay onto the tablet. However, this approach may be burdensome to the user (e.g., a radiologist) and result in user dissatisfaction. In addition, taping the paper or plastic overlay over the tablet may be an unsatisfactory long term solution.